This invention relates to a device for controlling the firing current of a blowback-operated, electrically fired quick-firing weapon, comprising a signal transmitter signalling the closed position of the slider.
A quick-firing weapon comprises a mechanism, which feeds each cartridge and pushes it into the barrel, closes a breech and automatically ejects the empty cartridge after the shot has been fired. Conventionally the breech is a slider. In prior art quick-firing weapons, firing is effected electrically by means of a firing current. A signal transmitter in the form of a slider contact monitors the closed position of the slider and prevents the triggering of the shot, if the slider is not in its closed position. In prior art quick-firing weapons in aircraft, the mechanism is driven by a motor and is thus positively actuated. Such a drive motor has to apply high power with the usual high rates of firing. Therefore, it has to be undesirably bulky and heavy and represents a considerable load on the aircraft electrical power supply. Another problem arising in a quick-firing weapon having a breech mechanism positively actuated by a motor is the following. It can happen, though only at a very low percentage, that a cartridge fires only after a noticeable firing delay. With a quick-firing weapon having a motor actuated breech-mechanism this can result in the not-yet-fired cartridge being ejected rather than the empty cartridge case, this cartridge then firing outside the weapon in a cartridge case receptacle. This would, of course, be a highly dangerous malfunction.
Therefore prior art quick-firing weapons used as aircraft arms have been designed as blowback-operated weapons. In this type of quick-firing weapons the breech-mechanism is actuated by the blowback of the preceding shot. This makes sure that the breech-mechanism is not operated to eject the cartridge case before the cartridge in the barrel has fired. However this type of quick-firing weapon would result in a failing cartridge, i.e. a cartridge which does not fire at all, making the weapon inoperative. In this case in the absence of blowback the breech-mechanism would not be actuated anymore and the non-fired cartridge would remain in the barrel.
For this reason, a charging cartridge is provided. If no firing of the cartridge and no actuation of the breech-mechanism takes place after the firing circuit has been closed, which is monitored by the slider contact, the charging cartridge will be fired after a preselected time delay through a time-delay relay. The gas pressure or blowback of this charging cartridge then causes, instead of the blowback of the shot cartridge, the breech-mechanism to be actuated. The failing cartridge is ejected. The weapon is charged with a fresh cartridge and the normal operating cycle of the weapon is restored. The delay time of the time-delay relay is selected to be longer than the maximum firing lag of the cartridge, for example, 300 milliseconds. This makes sure that no cartridge firing with lag can be ejected by means of the charging cartridge. Such a charging process makes the weapon again operative after failure of a cartridge. It is, of course, still not impossible that a still further failure occurs subsequently. For this case provision has to be made to enable a further charging process, i.e. a plurality of charging cartridge has to be provided, which are moved in succession into operative position by a charging mechanism. This results in further problems.
The rate of firing of the weapon is determined by the mechanical characteristics (mass, resiliency etc.) of the breech-mechanism and by the occuring gas pressures, which depend, among others, on the munition used. With a purely blowback-operated weapon, there will be an inherent rate of firing which may be variable within certain limits and may have undesirably high values. Also the charging mechanism for feeding the charging cartridge would have such an inherent rate of firing, which, however, due to the smaller mass is considerably higher than the inherent rate of firing of the weapon itself. This would have the result that, after a charging process, the next charging cartridge would be in its operative position very quickly, for example after 7.5 milliseconds, and would be fired by the, then still applied, charging pulse. Thus there would be the risk of double-charging. In order to avoid this, the time and duration of the charging impulse would have to be determined with high accuracy. This cannot be achieved with the relay circuits used in prior art electrically fired quick-firing weapons.